AITA For Explaining My Sexuality to My 10 Year Old Niece

I (28F) am an asexual woman. I have never dated or been interested in dating. I knew around the age of 13 that I was not developing crushes or even urges in the same way that my peers were. When I voiced this to my parents, they got me in with a therapist who specializes in queer people's mental health. Because of this, I am very confident in my sexuality and I do not feel the need to change myself to "fit in". I have close friendships that I value, and up until last night, I had a great relationship with my brother (30M) and his wife (32F).

Last night I was over at my parent's for dinner and my brother and his wife were there with my niece, Lily (10F). My niece loves me and I love her, we always end up sneaking away from the adults to play dolls together. This is my only real time with kids as I will never have any of my own, and I value it greatly. Lily and I were playing a board game while the other adults were talking politics in the dining room, and she asked me why I don't have a husband.

I told her I don't date because I am happy just having close friends. She was curious about this as it's obviously different from anyone she knows in life currently. She kept asking questions like had I ever dated before, why don't I like men, stuff like that. The conversation was very innocent, I would never cross a boundary about talking about anything explicit, and I just explained that I had never been interested in dating and liked living alone.

After we all went home for the night, I thought little more of the conversation. This morning I woke up to angry texts from both my brother and his wife about how I was trying to "corrupt" Lily with my lifestyle. Apparently, she told her parents that she thinks that she is "Asexual" and doesn't want to date anyone ever.

I replied that she's a 10 year old girl who shouldn't have any interest in dating at this age and all I did was answer her questions. They said that it was an inappropriate topic to discuss with her, and that they'll think twice before letting me spend time around her alone again. By this point, I was furious. I called them stupid and unrealistic for thinking that a 10 year old with unlimited access to the internet was too young to understand why her aunt is alone.

I stopped responding after that, but they continued to send some pretty colorful texts. I stand by what I said, but my mom also chimed in that she thinks the conversation was inappropriate. My dad doesn't really care, and my close friends are on my side.

So, AITA?

Edit for info so this doesn't get lost in comments: She asked if I was "gay" or a "lesbian". I figured if she understood these terms, she could understand the term that means neither. I told her that I was asexual, and it just means that I don't date anyone. That was the end of the conversation, and there was no talk of sex AT ALL.